Polarized direct-current contactor



Sept. 23, 1947. D. w. EXNER POLARIZED DIRECT CURRENT CONTACTOR Filed Airn 27, 1943 WITNESSES: INVENTOR Donald [4/ Elmer:

I BY M Ma. Wm

ATTORNEY Patented Sept. 23, 1947 UNITED STATES PATENT OFFICE POLARIZEDDIRECT-CURRENT CONTACTOR Donald W. Exner, Lima, Ohio, assignor toWestinghouse Electric Corporation, East Pittsburgh, Pa., a corporationof Pennsylvania My invention relates to contactors and, moreparticularly, to a combination polarity-determining contactor andcircuit making and breaking device for use in battery charging circuits,or the like.

In circuits, for example, such'as those normally used in railway carlighting and aircraft service in which the electromotive force isacquired from batteries and in which it is necessary to service andinspect the electric installation, it becomes necessary to have adequateprotective means for preventing the batteries from being connected tothe usual charging devices in areverse manner. It is obvious that if abattery were connected in a reverse manner to a charging device saidbattery would become deenergized,

therethrough. Such a structure in itself obviously could not be used toprotect a battery from faulty connection with a charging device.However, inakeeping with the teachings of my invention I have providedmeans for preventing the full energization of said coil except when thecurrent flowing through the coil is in a given predetermined direction.I

It is, therefore, an object of my invention to provide apolarity-determining device to be associated with a charging circuit fora battery which will function as a main contactor and at the same timewill prevent the battery from being connected to the circuit except whenthe current will flow in the proper direction without the use or need ofany auxiliary directional relays or the like.

Another object of my invention is to provide a polarity-determiningcontactor for a battery charging system embodying an auxiliary contactand actuating means which are responsive to the polarity of the chargingsystemand which will permit the main contactor to close or becomeengaged only if the resulting charging current will fiow in the correctdirection.

A further object of my invention is to provide a polarity-determiningcontactor and switching device which is actuated by means of anelectromagnet and which has associated therewith a permanent magnetutilized to actuate an auxiliary contact only if the polarity. of thecharging source is in the proper direction.

And a still further object of my invention is to modify and improveexisting direct current con- Application April 27, 1943, Serial No.484,715

4 Claims. (Cl. -320) 2 tactors for use as directional relays as well ascircuit makers and breakers by associating therewith a rotatablymounted. permanent magnet which actuates an auxiliary contactor utilizedto regulate the energization of the main electromagnet only when saidelectromagnet is energized by the correct flow of current therethrough.

Other objects and advantages of my invention will either be pointed outspecifically in the course of the following description of a deviceembodying my invention or will be apparent from such description, inwhich:

Figure l is a view in side elevation of a relay constructed inaccordance with my invention and illustrating how the relay may beconnected into a circuit.

Fig. 2 is a fragmentary enlarged view of a portion of my relaystructure; and

Fig, 3 is a view taken along the line III--II[ of Fig. 1.

Referring to the accompanying drawing, there is shown a direct currentcontactor or relay embo'dying a substantially L-shaped soft iron frame Hand a soft iron core I! rigidly attached therecircuit. A bracket [5 isrigidly attached to the armature l4 and has a forwardly and upwardlyextending end l5 disposed at the upper or hingable end of the armatureI4. Thebrackets l3 and ii are notched so as to fit together and providemeans for oscillatory movements of armature It. A bolt l 6 passesthrough the two projections I3 and .I5' and has a compression spring l1positioned thereabout to normally hold the armature in position, asshown, upon the upper end of the frame II, in keeping with the teachingof Willard G. Cook in Patent 1,753,983, as-

signed to theassignee of this invention. A nut I8 is threaded upon thelower end of the bolt to compress the spring I! and bias the bracket l5toward the bracket Ill. The biasing action of spring I! thus permits thearmature II to oscillate about the upper end of the frame II as afulcrum.

I A movable contact I! is rigidly attached tothe able contact I3 engagesa stationary contact 2|) when the armature I4 moves to a closedposition. The stationary contact 26 is rigidly attached to a rearwardlyextending insulating member 22, which is positioned below core I2, bymeans of a bracket member 23 and terminal member 24a. The insulatingmember 22 is attached at one end thereof to the frame II. The contactsI3 and 26 are the main contacts and are connected in series with thebattery charging circuit so as to connect a battery 2|- with a chargingdevice (not shown) when it is desired to charge the battery, as ishereinafter more fully described.

An actuating coil 24 is positioned about the core I2 and is connectedacross the buses 33 and 46, leading to the charging device (not shown),by means of conductors 31 and 33 so as to receive current therefrom.Coil 24 causes the armature I4 to assume the contact closing positionwhen the current is flowing in a proper direction through coil 24 as ishereinafter more fully described.

An upwardly extending L-shaped soft iron bar or arm 25 is either formedintegrally with or rigidly attached to the upper portion of the exposedend of the core I2. This arm 25 extends toward the upper end of the softiron frame II. A second or downwardly extending arm 26 is rigidlyattached to the lower surface of the frame II so as to extend towardsthe core I2. The second arm 26 is positioned inwardly from the upper endof the frame a sufllcient distance to permit a rotating permanent magnet21 to be positioned between said arm 26 and the arm 25 attached to thecore I2. With the two arms 25 and 26 rigidly attached to the core I2 andthe frame II, respectively, it is obvious that a certain portion of theflux flowing through the core I2 and frame II will pass outwardly alongsaid arms and through the permanent magnet 21 located therebetween.

manner.

when the charging circuit is connected in a proper The resistor isinitially connected in series with the coil 24 to reduce the quantity ofcurrent flowing therethrough so as to reduce the electromagnetic effectdeveloped by said coil when the circuit is connected in a reverse order.This prevents the armature II from being drawn into a contact closedposition and thus prevents the battery 2| from being connected to thecharging device in a reverse manner.

In the operation of a relay embodying my invention one terminal of thebattery 2| is con- -nected to a flrst terminal of the coil 24 throughconductor 31 and to the charging device (not shown) through conductor38. The second terminal of the battery is connected to the main relayterminal 24a and stationary main contact 23. Th'emovable main contact I9is connected to the second terminal of the charging device by conductor43 through the armature I4, frame II, main terminal 24b attached to saidframe and conductor 36. The second terminal of the energizing coil 24 isconnected to the stationary contact 32 and one side of resistor 35 byconductors 39 and 39a. The second side of resistor 35 and the movableauxiliary contact 3| are connected together by conductor 4| to provide ashunting circuit around the resistor 35 and are also connected to theconductor 36 and the second terminal of thecharging device throughconductor 4|).

When the buses 38 and are energized current from the charging device(not shown) will flow only through the resistor 35 and the coil 24 aslong as the main contacts I! and 20 are open. The resistor 35 being inseries with the coil 24 substantially reduces the flow of currenttherethrough'. However, said coil 24 will de- The permanent magnet 21 isa relatively small member rotatably mounted by means of a nonmagneticpln 23 which passes transversely therethrough. Said pin 26 is supportedby a nonmag netic bracket 23 attached to the end of the frame The magnet21 is thus supported between the arms 25 and 26, in this instance, withits north pole positioned upwardly. The magnet 21 is therefore, free tomove about the pin 28 in response to the direction of flow of themagnetizing force between the two arms 25 and 26.

A contact carrying arm 33 is rigidly atached to the upper or north poleend of the permanent magnet 21 so as to move in response to themovements of the permanent magnet 21. A movable auxiliary contact 3| islocated upon the free end of the arm 36 so as to engage a stationaryauxiliary contact 32, when the current flowing through the coil 24 isindicative of a proper direction of flow of the current through thecharging circuit. If the flow of current through the charging circuitwould be in a reverse or improper direction, said permanent magnet 21will rotate in a clockwise direction maintaining the mov able auxiliarycontact 3| in engagement with a stop member 33. The stationary auxiliarycontact 32 and stop portion 33 are supported by insulating brackets 34and 34', respectively attached to the frame I I.

A resistor 35 is connected in series with coil 24 when the relay isfirst energized. However, the auxiliary contacts 3| and 32 close orconnect a shunting circuit 33a-4I around the resistor 35 velop a certainpredetermined quantity of magnetizing flux in a clockwise orcounterclockwise direction through the frame I I, armature I4 and coreI2, depending upon the direction of the cur-.

rent flowing through coil 24. In addition, a certain quantity ofmagnetizing flux will pass through arm 25 and 26 and permanent magnet2'|. If the current from the charging device has an improper direction.the magnetic flux through the relay causes arm 25, to become a southpole while arm 26 becomes a north pole (see Fig. 2). The permanentmagnet '21, having its north pole extending upwardly, will then bebiased in the clockwise direction and maintains the auxiliary contacts32 and 3| in an open position. The magnetic flux now developed by coil24 is insufllcient to draw the armature I4 into closed position becauseresistor 35 remains effective in series with coil 24 and weakens itsexcitation.

However, when the system is connected to the charging device in. a,proper manner so that the current flowing therefrom is in the correctdirection to charge the battery 2|, the flux developed by the coil 24causes arms 25.and 26 to become a north pole and south polerespectively. The permanent magnet 21 is then rotated in acounterclockwise direction and moves the auxiliary contact 3| intoengagement with the stationary auxiliary contact 32. A shunting paththrough conductor 4| and cooperating auxiliary contacts 3| and 32 istherefore established across resistor 35. Accordingly, the coil 24 isnow connected directly across the charging device so that an increasedmagnetic flux is developed by the coil. This increase in flux will drawthe armature I4 downwardly against the core I2, and

the main contacts l9 and 20 close and connect the charging devicebuses38 and 40) to the battery 2 l.

When using the relay embodying my invention in battery chargingcircuits, for example, it is apparent that the batteries cannot beconnected to the charging device except in a proper manner. Thisprotection is obtained without the use of any auxiliary or secondaryrelay or protective device, a vfeature which results in a reduced amountof metal being used and a considerable reduction in weight and spacerequired.

Various modifications may be made in the device embodying my inventionwithout departing from the spirit and scope thereof, and I- desire,therefore, that only such limitations shall be placed thereon as areimposed by the prior art and the appended claims.

2 claim as my invention:

1. An electromagnetic direct current contactor, comprising main contactsand auxiliary con- 'tacts, a stationary soft-magnetic structure having aleg portion and a core portion extending substantially in parallel toeach other, an armature disposed for controlling said main contacts andbeing pivoted on said leg portionior angular motion toward and away fromsaid coreso as to form a first magnetic flux path therewith, springmeans for biasing said armature away from said core, two magnetizablepole pieces mounted on said leg and core portions respectively andextending toward each other so as to form a field gap between them inmagnetic arallel arrangement to the gap'iormed between said core portionand said armature when the latter is in its position away from said coreportion, a permanent magnet member disposed for controlling saidauxiliary contacts and being r0- tatably mounted in said field gap, anenergizing coil disposed on said core portion, terminal means for spplying direct current to said coil, and ourrent-limiting circuit meanscontrolled by said auxiliary contacts for reducing said current to anamount insufiicient for closing said armature against its bias when saidpermanent magnet is in a given position depending upon the polarity ofsaid current.

2. A direct-current contactor, comprising a soft-magnetic structurehaving a stationary core member and an armature movable toward and awayfrom said core member, said armature forming a magnetic circuit togetherwith said core member, spring means for biasing said armature away fromsaid core member, an energizing wind-- ing for providing magnetizationfor said core member in order to cause said core member to move saidarmature when said magnetization is stronger than the armature bias, apermanent magnet pivoted on said structure so as to be movable betweentwo positions and being arranged to form a shunt path in said magneticarmature disposed for controlling said main contacts and being disposedrelative to said structure so as to form a first magnetic flux paththerewith, said armature being movable between two positions relative tosaid structure and biased for motion away from said structure, apermanent magnet member disposed for controlling said auxiliary contactsand being movable between two positions relative to said structure, saidstructure having poles extending close to said magnet member so as toform therewith a second magnetic fiux path, an energizing windingdisposed onsaid structure, terminal means for supplying direct c'urrentto said coil, and-circuit means controlled by said auxiliary contactsand connected with said winding for preventing said winding from movingsaid armature against its bias when said permanent magnet member is in agiven one of its two positions depending upon the polarity of saidcurrent.

4. An electromagnetic direct current contactor, comprising main contactsand auxiliary contacts, a stationary soft-magnetic structure having aleg portion and a core portion extending substantially in parallel toeach other, an armature disposed for controlling said main contacts andbeing pivoted on said leg portion for angular motion toward and awayfrom said core so as to form a first magnetic flux path there with,means for biasing said armature away from said core, a permanent magnetmember disposed for controlling said auxiliary contacts and beingpivotally mounted on said structure between said leg and core portionsso as to form therewith a second magnetic flux path in parallel to saidfirst fiux path, and an energizing coil disposed on said core portion,terminal means for supplying direct current to said coil, and circuitmeans controlled by said auxiliary contacts and connected with said coilfor preventing said armature from being moved by said core portionagainst the armature bias when said permanent magnet member is in agiven position depending upon the polarity of said current.

DONALD W. EXNER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,142,852 Simon June 15, 19152,245,391 Dicten June 10, 1941 374,673 Griscom Dec. 13, 1887 569,634Gharky Oct. 20, 1896 698,027 Knapp Apr. 22, 1902 821,586 Gough May 22,1906 1,837,188 Keller Dec. 22, 1931 733,627 Cox July 14, 1903 2,126,562Lakatos Aug. 9, 1938 2,284,755 Melick June 2, 1942 2,081,991 Exner June1, 1937 892,655 Duryee July 7, 1908 969,345 Culver Sept, 6, 19101,193,537 Girardeau Au 8, 1916 1,250,152 Eisenmann Dec. 18, 19171,507,300 Replogle Sept. 2, 1924 1,752,900 Eisenmann Apr. 1, 1930863,692 Bliss Aug. 20, 1907 1,989,057 Kongsted Jan. 22 1935

